This invention relates to cellular communication systems. Specifically, the invention is directed to mobile station supported private system roaming.
A description of cellular radio systems is found in Cellular Radio Systems, published by Artech House, Boston (editors: D. M. Balston and R. C. V. Macario; ISBN: 0-89006-646-9); Digital Cellular Radio written by G. Calhoun and published by Artech House, Boston (ISBN: 0-89006-266-8); and TIA IS-136 air interface standard (xe2x80x9cIS-136xe2x80x9d). Cellular Radio Systems, Digital Cellular Radio, and IS-136 are hereby incorporated by reference in their entirety.
A cellular mobile telecommunications system includes a mobile communication unit or mobile station communicating with any one of a plurality of geographically spaced base stations. Broadly, each base station defines a cell, and each cell forms an integral part of a larger cellular network. The size of a cell largely depends on the power rating of the corresponding base station. The base stations communicate with a mobile switching station by means of intercellular trunk lines. The mobile switching center determines which of the base stations and channels should process a call with the mobile station based on considerations such as signal strength between each available channel and the mobile station.
A mobile station can also communicate with a private system such as a digital wireless office system. A digital wireless office system provides an extension to the private branch exchange (xe2x80x9cPBXxe2x80x9d). The mobile station can, for example, communicate with the private system based on the ANSI-136 standard. The ANSI-136 standard is hereby incorporated by reference in its entirety. The terms xe2x80x9cprivate systemxe2x80x9d and xe2x80x9cprivate communication systemxe2x80x9d will hereafter be regarded as equivalent terms.
A mobile station can roam between private systems. Specifically, a mobile station can roam between a private system and the public cellular system using an ANSI-41 connection. A mobile station can also roam directly between private systems, and indirectly by roaming from a first private system into the public system and then into a second private system.
Problems can arise when a private system lacks information on a user. Information about a user, such as a user""s profile and location, can be kept in a location register (xe2x80x9cLRxe2x80x9d) such as a Home Location Register (xe2x80x9cHLRxe2x80x9d) on a Public Land Mobile Network (xe2x80x9cPLMNxe2x80x9d). However, private systems are not able to access user information stored on a public land mobile network HLRs, and public land mobile network HLRs generally do not store information about private systems. Such information is necessary to determine whether the mobile station should be offered service for the automatic routing of calls of that private system. Centralized or distributed private database solutions that offer user information may require administration of routing on a per user basis. Thus, centralized or distributed private database solutions would incur a considerable overhead and set up costs.
The present invention is directed toward overcoming one or more of the problems set forth above.
In one aspect of the present invention, a mobile communication unit for a private system is provided including a transceiver communicating with a plurality of private wireless office systems of a private network, a memory storing user group information, and a processor selectively initiating transmission of the user group information in the memory by the transceiver. The user group information identifies a location register storing information relating to access rights of the mobile communication unit on the private wireless office system with which the transceiver is then communicating, and transmission of the user group information initiates determination of access rights with the private wireless office system with which the transceiver is then communicating.
The location register may be a remote private location register; and the user group information in the memory may be a mobile switching center identification of the private location register.
A remote private location register may store the information relating to access rights at an Internet address, with the user group information in the mobile communication unit memory being the Internet address of the private location register.
The user group information may be an identification transmitted by the transceiver, with a private translation table correlating the identification with the location register.
The processor may also initiate transmission of the user group information to the one private wireless office system with which the transceiver is then communicating only upon receipt by the transceiver of a signal indicating that the one private wireless office system with which the transceiver is then communicating supports use by private system mobile communication units. Also, the processor may block transmission of the user group information to the one private wireless office system with which the transceiver is then communicating upon receipt by the transceiver of a signal indicating that the private wireless office system with which the transceiver is then communicating does not support use by private system mobile communication units.
In another aspect of the present invention, a communication system for a private system is provided, including first and second spatially separated private wireless office systems covering first and second areas, a mobile station, a private location register (xe2x80x9cPLRxe2x80x9d) at a selected location storing access right information for the mobile station, and a communication network between the private wireless office systems and the PLR. The user group information identifies the selected location. The mobile station has a transceiver communicating with the private wireless office system covering the area in which the mobile station is located, a memory storing user group information relating to the mobile station, and a processor selectively initiating transmission by the transceiver of the user group information in the memory to the private wireless office system covering the area in which the mobile station is located.
The communication network may be the Internet with the user group information an Internet address for the private location register on the Internet.
Further, the communication network may identify each private wireless office system by a Mobile Switching Center Identification (MSCID), with one of the first and second private wireless office systems having the private location register and the user group information being the MSCID for the private wireless office system which has the private location register.
Translation tables at each base station may map the user group information to the private location register storing access right information for the mobile station.
In still another aspect of the present invention, a method for registering a mobile station having a home private wireless office system with a visited private wireless office system is provided, comprising the steps of transmitting user group information by the mobile station to the visited private wireless office system when initiating registration of the mobile station with the visited private wireless office system (the user group information identifying the home private wireless office system), requesting information regarding service access of the group from a private location register of the home private system responsive to receipt of the user group information at the visited private wireless office system, providing the requested information regarding service access of the group from the private location register of the home private wireless office system to the visited private wireless office system, and providing service access to the mobile station in the visited private wireless office system in accordance with the information regarding service access of the group.
The step of requesting information regarding service access of the group from the private location register at the home private wireless office system may comprise translating the user group information to the private location register, and accessing the information regarding service access of the group at the private location register of the home private wireless office system.
The step of transmitting user group information by the mobile station to the visited private wireless office system when initiating registration of the mobile station with the visited private wireless office system may be done only if it is determined that the mobile station is not initiating registration with the home private wireless office system. Further, an indication may be transmitted by the visited private wireless office system that it supports communication with mobile stations registered with private system networks, with transmitting user group information by the mobile station to the visited private wireless office system when initiating registration of the mobile station with the visited private wireless office system not being done unless the mobile station receives the indication.
Transmitting user group information by the mobile station to the visited private wireless office system when initiating registration of the mobile station with the visited private wireless office system may consist of transmitting a user group ID.
The private location register may be at an Internet address, with the step of requesting information regarding service access of the group from the private location register comprising requesting information regarding service access of the group over the Internet from the Internet address, and the step of providing the information regarding service access of the group from the private location register at the home private wireless office system to the visited private wireless office system comprising providing the information regarding service access of the group over the Internet from the Internet address.
The private location register may be identified by a Mobile Switching Center Identification (MSCID); with the step of requesting information regarding service access of the group from the private location register comprising addressing a request for information regarding service access of the group with the MSCID, and sending the request for information addressed with the MSCID to the private location register identified by the MSCID.
The user group information may be mapped in a translation table for identifying the home private wireless office system, with the step of requesting information regarding service access of the group from the private location register comprising mapping the user group information on the translation table to identify the home private wireless office system, and requesting information regarding service access of the group from the private location register identified by mapping the user group information on the translation table.